There is an ongoing investigation towards developing measurement techniques and equipment for measuring eye movement of humans. Various ophthalmologic, vestibular and neurologic tests exists which involves observing eye movements. Tests may comprise observation of eye movements during concurrent sight deprivation of either one eye or both eyes. Tests incorporating deprivation of sight of either one or both eyes may comprise HINTS tests, or individual parts of the HINTS tests, such as test of skew and/or tests of nystagmus.
Tests may comprise measuring fast eye movements, e.g. eye saccades, lasting approximately between 20-200 ms and involving angular speed up to 900 deg/s. Such fast movements may be visual to the clinician, but may be difficult to quantify consistently. Tests may comprise measuring very small eye deviations, e.g. skew, which may be difficult to detect and/or quantify subjectively.
It is desirable to circumvent subjective measurements and provide a possible standardized test, which is independent of the clinician or other person performing the test. Furthermore, in some environments, such as in pre hospital settings, it may be problematic, if not impossible, to accurately perform the test when relying on subjective measurements.
Furthermore, sight deprivation is conventionally performed by placing a black cover over the patient's eye. The cover may be a hard plastic or the hand of the clinician. Some devices may comprise a black cover, such as a visor, which is able to be lowered over the patient's eyes. However, it is desirable that a device capable of performing the above mentioned tests is able to control the deprivation of sight in an accurate, consistent, secure, comfortable, and easy way.